Erica Sadun has the scoop on the first developers accepted by Apple into the iPhone SDK program:

Five iPhone limit. For anyone hoping to find a back door way to distribute software, tough luck. You may develop for up to five iPhones and that’s it. So no distribution sans Apple.

Test devices are iBricks — so to speak. Adding the pre-release iPhone OS to your iPhone seems to kill actual phone functionality. Update: We have unconfirmed reports that some developer phones continue to work as expected; as soon as we can clarify this we will.

A small handful of developers have told me they got golden tickets yesterday or today, too.